1. Field of the Invention
This invention pertains to welding torches, and more particularly to a tungsten inert gas (TIG) welding torch having enhanced tactile qualities.
2. Description of the Prior Art
In TIG welding, a person directs the tip of a tungsten electrode and a stream of inert gas to a work surface. The electrode and passage for the gas are contained in a relatively small torch. Some TIG torches also include passages for water cooling. The torch includes a handle that in some instances is held in a person""s hand. The torch is connected to a flexible cable, which conducts electrical power from a welding machine to the torch. In air-cooled torches, the cable is incorporated into a hose that also delivers the inert gas to the torch. In water-cooled torches, the cable is incorporated into a water return hose. Two other hoses deliver the water and the inert gas to the torch. At the front end of the torch handle is a torch head or neck that includes a gas nozzle, an electrode-holding collet, a collet body, and a gas diffuser. The torch head is usually angularly offset from the handle.
TIG torches can be held in various ways. One way is to place the torch handle in the palm of a person""s hand like a hand rail and then curl several fingers around the handle. Another way to hold the torch is between the thumb and first two fingers like a pen or pencil.
Prior TIG torch handles were usually cylindrical in shape. That shape made it easy and comfortable for the person to hold in the first way and manipulate the torch for proper welding action. However, the prior cylindrical torch handles had disadvantages. Their shapes were uncomfortable to hold in the second way, e.g., like a pen or pencil. For example, the cylindrical surfaces were prone to move, both rotationally and longitudinally, between the person""s fingers and thumb. That was especially true if the person was wearing gloves. Consequently, to prevent movement, the person had to hold the torch with a greater force than was desirable.
One attempt at improving a TIG torch involved making a handle with an enlarged gripping area. U.S. Pat. No. 5,916,465 shows a TIG torch with a generally spherical cover made of a resilient material. The combination of the resilient material and the enlarged area of the cover increased the mechanical advantage when held between the person""s palm and fingers. The U.S. Pat. No. 5,916,465 patent also teaches some longitudinal grooves in the torch handle. Neither the spherical cover nor the grooves provided any benefit regarding angular orientation of the torch in the person""s hand or holding the torch like a pencil.
Other prior TIG torch handles were covered with generally cylindrical sleeves made of relatively soft synthetic materials. Those torch handles, too, lacked any orienting qualities, and they provided little help with the movement problem for the various ways of holding the torch.
U.S. Pat. No. 5,571,427 discloses a TIG torch having a torch handle with a generally D-shaped cross-section. The D-shape improved the ergonomic fit and resistance to movement compared with cylindrical torch handles when held in the first manner. On the other hand, the round portion of the handle rendered it uncomfortable for the fingers when the torch was held like a pen or pencil.
Thus, despite previous attempts to improve the holding characteristics of TIG torches, further improvements are desirable.
In accordance with the present invention, an ergonomic tungsten inert gas (TIG) torch is provided that is both more comfortable and more convenient to hold than prior torches. This is accomplished by contouring the torch to suit the fingers of a person holding it like a pen or pencil.
The torch of the invention may be water-cooled or air-cooled. In a water-cooled torch, a longitudinally extending gas tube joins to a barrel, which is usually angularly offset from the longitudinal direction of the gas tube. The gas tube communicates with the interior of the barrel. The barrel holds the welding electrode. A water inlet tube and water outlet tube run longitudinally in close proximity to the gas tube. The water inlet and outlet tubes may be a continuous tube that loops around the barrel and doubles back on itself. The water and gas tubes and the barrel form a skeleton of the torch. Flexible hoses connect the water and gas tubes to the welding machine. A braided cable inside one of the water hoses conducts electrical power to the torch.
In an air-cooled torch, the skeleton is comprised of the gas tube and the barrel. The gas tube may contain a valve that is used to control the flow of the inert gas. A single hose connects the torch to the welding machine. The hose also contains a braided electrical power cable.
The torch skeleton is covered with a contoured grip. According to one aspect of the invention, the grip is molded from a thermosetting plastic material that remains slightly soft and resilient after curing. The grip material fills the spaces between and around the water and/or gas tubes and provides some mechanical strength to the torch. A back end of the grip is designed to be captured in one end of a rigid sleeve that is part of the torch.
It is a feature of the invention that the exterior surface of a head of the grip is contoured in a manner that renders it exceptionally comfortable to hold like a pen or pencil in a person""s fingers. For that purpose, the contour of the grip head diverges in a smooth non-linear manner toward its ends. For example, the grip head contour may have a concave shape in longitudinal cross-section.
The grip head contour is further formed with multiple flattened gripping areas spaced around the circumference of the grip head. The gripping areas are relatively long compared with their widths. In a preferred embodiment, there are multiple gripping areas. The first may be perpendicular to and symmetrical about a first longitudinal plane through the grip head. A second gripping area lies in a second longitudinal plane that makes an angle of between approximately 10 degrees and 30 degrees with the first longitudinal plane. A third gripping area lies in a third longitudinal plane that is on the opposite side of the first longitudinal plane as the second gripping area. The third gripping area also makes an angle of between approximately 10 degrees and 30 degrees with the first longitudinal plane. All the gripping areas are preferably equidistant from the grip head longitudinal axis. Each gripping area preferably has a textured non-slip surface.
When a person holds the torch head like a pencil, the forefinger contacts the first gripping area. Simultaneously, the person""s thumb contacts the second or third gripping area, and the side of the person""s middle finger contacts the remaining gripping area. In the preferred embodiment, the gripping areas are further arranged such that the longitudinal plane to which the first gripping area is perpendicular contains the longitudinal centerline of the electrode.
The flat textured gripping areas provide several benefits to TIG torches. As one benefit, the gripping areas render the torch resistent to rotation between the person""s fingers. Consequently, the person need not exert as much gripping force as with prior torches to keep the torch in place. A second advantage is that the gripping areas provide an inherent orientation of the torch electrode relative to the person""s fingers. The person is thus able to quickly establish correct orientation of the electrode to a workpiece.
Other advantages, benefits, and features of the present invention will become apparent to those skilled in the art upon reading the detailed description of the invention.